Beliefs:
	/* The agent will strongly prefer to visit only odd floors.
	   Random part is added to decide ties automatically.
	 */
	cost(CurrentPlan, NewStop, _, Cost) :- (0 is (NewStop mod 2)), 
	                                       Cost is (10 + rand).
	
	cost(CurrentPlan, NewStop, _, Cost) :- (1 is (NewStop mod 2)),
	                                       Cost is (0 + rand).                                    
	                                       
